Appendix Cancer Has Quadrupled in Millennials

Cancer is generally a disease of old age. But researchers are increasingly finding that certain types—including colon, breast, stomach, and pancreatic cancers—are hitting people younger than 50 far more commonly than they used to.

In a new report, published in the Annals of Internal Medicine, researchers at Vanderbilt University focus on a relatively rare cancer—appendiceal cancer, which occurs in the appendix—and found that its rates are also rising, especially among millennials.

Andreana Holowatyji, assistant professor of hematology and oncology at Vanderbilt University Medical Center, and her colleagues analyzed data from the National Cancer Institute’s Surveillance, Epidemiology and End Results program, a cancer registry that includes patients from 1975 to 2019. The scope of the dataset allowed them to look for generational differences in cancer rates. They specifically tracked appendix cancer, which for many years was misclassified as colorectal cancer since the appendix sits at the start of the large intestine.

Recent studies have shown an increase in colorectal cancers among those under 50, and Holowatyji wanted to learn if the same trend was occurring for appendix cancer. “We don’t know what the risk factors are for appendix cancer, and seeing whether there are generational effects could help us to continue to put the pieces together of this complex puzzle,” she says.

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In their analysis, which involved more than 4,800 people diagnosed with appendix cancer, rates of the cancer tripled among those born in 1980—and quadrupled among those born in 1985—compared to people born in 1945. Rates increased in every birth cohort after 1945. In that time, rates of appendectomies remained about the same, which the researchers say largely rules out the possibility that more cases were detected from appendectomies performed.

It’s likely not a single factor but the interaction of several that contributes to an increased cancer risk in this age group, such as rising rates of obesity and metabolic syndrome as well as environmental exposures, Holowatyji says. “The challenging thing now is to disentangle not only what these exposures are, but what molecular changes these exposures cause, and what the consequences of those changes are on our cells that may end up increasing the risk of carcinogenesis,” she says.

Much more data is needed to better understand appendiceal cancer, and that starts with greater awareness and better diagnosis. Because it’s rarer than colorectal cancer, Holowatyji says health care professionals and the public should be more attuned to potential symptoms and not ignore or dismiss them. These can include general complaints like bloating, changes in bowel movements, and loss of appetite. If they persist, people should see their doctor.

Half of appendix cancers are diagnosed after it has already spread, so being more vigilant and intervening early could lead to better outcomes. “While rare, appendix cancer is rising,” she says. “Individuals know their bodies best, and if they experience any changes or symptoms, those aren’t things they should overlook.”